Compiler: Generate .scp files as part of the build process.

Stolen from SM (https://github.com/alliedmodders/sourcemod/pull/112).

compiler/libpc300/AMBuilder

@@ -1,9 +1,50 @@
 # vim: set sts=2 ts=8 sw=2 tw=99 et ft=python:
 import os.path
 
+# Build the packing binary garbage.
+scpack = AMXX.Program(builder, 'scpack')
+if builder.target_platform == 'windows':
+  scpack.compiler.linkflags.remove('/SUBSYSTEM:WINDOWS')
+  scpack.compiler.linkflags.append('/SUBSYSTEM:CONSOLE')
+scpack.sources = ['scpack.c']
+scpack = builder.Add(scpack)
+
+# Generate pack files.
+packed_files = ['sc5', 'sc7']
+packed_includes = []
+for packed_file in packed_files:
+  # The absolute path to sc5-in.scp etc.
+  in_path = os.path.join(builder.currentSourcePath, '{0}-in.scp'.format(packed_file))
+
+  # The output file relative to the output folder, i.e. sourcepawn/compiler/sc5.scp.
+  out_path = os.path.join(builder.buildFolder, '{0}.scp'.format(packed_file))
+
+  # The absolute path to the build folder, i.e. /Users/.../sourcepawn/compiler.
+  build_folder = os.path.join(builder.buildPath, builder.buildFolder)
+
+  # scpack runs in ./sourcepawn/compiler/scpack/ so we build relative paths
+  # from there.
+  scpack_argv = [
+    os.path.join(builder.buildPath, scpack.binary.path),
+    os.path.relpath(in_path, build_folder),
+    os.path.relpath(os.path.join(builder.buildPath, out_path), build_folder),
+  ]
+
+  _, (entry,) = builder.AddCommand(
+    inputs = [scpack.binary, in_path],
+    argv = scpack_argv,
+    outputs = ['{0}.scp'.format(packed_file)],
+  )
+  packed_includes += [entry]
+  
 binary = AMXX.Library(builder, 'amxxpc32')
 
-binary.compiler.includes += [builder.currentSourcePath]
+binary.compiler.includes += [
+  builder.currentSourcePath,
+  os.path.join(builder.buildPath, builder.buildFolder),
+]
+
+binary.compiler.sourcedeps += packed_includes
 
 if builder.target_platform in ['mac', 'linux']:
   binary.compiler.defines += ['ENABLE_BINRELOC']